(AP) – There is evidence that having COVID-19 may not protect against infection again with some of the new variants.
People may also have a second infection with previous versions of the coronavirus if they build up a weak defense the first time, new research suggests.
How long the immunity of a natural infection lasts is one of the big questions of the pandemic.
Scientists still think reinfections are quite rare and generally less severe than the initial ones, but recent developments around the world have raised concerns.
In South Africa, a vaccine study found new infections with a variant in 2% of people who had an earlier version of the virus.
In Brazil, several similar cases have been documented with a new variant there.
Researchers are investigating whether reinfections help explain the recent outbreak in the city of Manaus, where it was thought that three quarters of residents had already been infected.
In the United States, a study found that 10% of Navy recruits who had evidence of previous infection and repeatedly tested negative before starting basic training were infected again.
That work was done before the new variants started to spread, said a study leader, Dr. Stuart Sealfon, of the Icahn School of Medicine at Mount Sinai in New York. “The previous infection does not give a free pass,” he said. “A substantial risk of reinfection remains.”
Re-infections represent a public health problem, not just a personal one.
Even in cases where reinfection does not cause symptoms or only mild symptoms, people can still spread the virus.
That is why health officials are recommending vaccination as a long-term solution and encouraging people to wear masks, keep physical distance and wash their hands frequently.
Doctors in South Africa began to worry when they saw an increase in cases late last year in areas where blood tests suggested that many people already had the virus.
Scientists have discovered a new version of the virus that is more contagious and less susceptible to certain treatments.
It currently causes over 90% of new cases in South Africa and has spread to 40 countries, including the United States.
Madhi led a study testing the Novavax vaccine and found that it was less effective against the new variant.
The study also revealed that infections with the new variant were just as common among people who had COVID-19 as those who did not.
California scientists are also investigating whether a recently identified variant may be causing reinfections or an increase in cases there.
We want to hear from you! Send us an email to [email protected] and follow @thejamaicastar on Instagram and Twitter @JamaicaStar, and on Facebook: @TheJamaicaStar.